This Project investigates how the brain computes the values that rewards have for other people. While the prior two Projects study social decision-making that is based on the value that stimuli have for the person making the decision, this Project 3 studies decisions about the values rewards have for another person. Examples include altruistic behaviors, such as sacrificing food for a child or giving a donation to charity, but also encompass strategic and manipulative behaviors, such as a car salesman's need to figure out how much a customer might value a used car. These abilities are related to empathy and theory-of-mind, likely rare in other animals, and feature pronounced individual differences that can merge into pathology in mental illnesses such as autism. This Project will use the same computational framework as in Project 1, dissecting the neural signals that correlate with the value of decisions benefiting others at the time of choice, and with the values of the outcomes of those decisions (seeing somebody else get a benefit as a consequence of your decision). Only a handful of studies have addressed this topic, yet like the observational learning topic of Project 2 it is ubiquitous in human behavior. This Project continues our multimodal approach, using both fMRI and electrophysiological recordings, and investigating both humans and monkeys. Two Specific Aims compare the neural mechanisms behind processing decision values and experienced values for oneself, or for another person. A third Aim investigates how these mechanisms may be modulated by social context: if the other person is a stranger or familiar, or if they are judged to be deserving or not, and if the subject herself is being watched by others or not. A final fourth Aim leverages the data from Core 3 in an exploratory investigation of individual differences.